The collected data of falling time were recorded. Figure (6) shows a graph of the switching falling time versus applied voltage. A nonlinear graph is obtained with the average of switching falling time of 2.89 ns. The developed circuit also produced negative voltage and small ripple in nanoseconds scale. The maximum negative voltages were measured and represented in Figure (7). The negative voltages were in linear relationship with the applied voltage. In certain case, this voltage could increase the Q-switching efficiency due to the full retardation of laser beam. For commercial purpose, the circuit should produce sharp pulse with small ripple. The high voltage supplied to the avalanche transistor caused it to change its shape due to the piezoelectric effect. This effect could be eliminated by adding RC component in the circuit. Furthermore, by using PIC microcontroller, the pulse duration of trigger signal easily adjusted and controlled. In addition, the developed circuit also able to operate in high repetition rate mode up to 1 MHz.